1. Field of the Invention
The present invention relates to a process for the vapor growth of a thin film and, more particularly, to a process for the vapor growth of a thin film having a uniform thickness on a plurality of wafers.
2. Description of the Prior Art
The vapor growth technique is widely employed for growing a thin semiconductive, conductive or insulating film, on a substrate or wafer. The wafer is used for the manufacture of semiconductor devices referred to as IC, LSI and the like. In the vapor growth technique, a reaction gas are caused to flow through a reaction tube under normal or reduced pressure and brought into contact with the wafers arranged in the reaction tube.
In accordance with the requirement for increasing the production rate of wafers with a thin film thereon, the vapor growth process is widely performed under a reduced pressure, for example, 10 Torr. In this vapor growth under a reduced pressure, a plurality of wafers can be simultaneously treated in the reaction tube which usually has a circular cross-sectional space therein.
The conventional vapor growth process under a reduced pressure is, however, disadvantageous in that the thickness of a film grown on one piece of wafer by such process can occasionally be nonuniform. As a result of this nonuniform thickness of the thin film on one piece of wafer, the subsequent processes for treating the wafer, such as etching of the thin film, may become very complicated in order to produce a uniformly thick film all over the wafer after completion of such treating processes.